Also disclosed in the document EP-B1-1 093 902 in the name of the applicant is a method for manufacturing a bendable thermoplastic reinforcement of U-shaped section, for example, for such profiled seals, said reinforcement having a central portion and two arms each comprising a series of symmetrical limbs which are separated from one another by slots. Said slots are obtained exclusively by calendering (i.e. without a post-forming operation) by the passage of the thermoplastic material between an engraved male wheel along a hollow cavity (i.e. defining the “negative” shape of the profiled reinforcement to be obtained) and a female wheel which tangentially covers said male wheel and which is driven in synchronous co-rotation therewith.
Calendered reinforcements set forth in this document provide satisfactory results. However, experience has shown that said calendered reinforcements do not always allow the profiled elements incorporating said reinforcements to be provided with sufficient clamping values to be held on the rebate, in contrast to a profiled element with a metal reinforcement. It is thus necessary either to increase the thickness of the limbs of the reinforcement or to modify the geometry thereof. Moreover, the profiled elements incorporating said reinforcements may have an overall appearance of “dog ribs” i.e. an unequal covering of the arms of the reinforcement by the coating material extruded on said reinforcement, thus impairing the appearance of the profiled element. Moreover, the cost of the material of the covering is high and greater than that of the material of the reinforcement.